he was james holmes, a medical student. police say he acted alone. they still do not know why he did it. he told police his apartment was booby trapped. it was. tripwires and explosives were found. nearby buildings were evacuated. >> his apartment is booby trap with various incendiary and chemical devices and apparent tripwires. we have an active and difficult there.eicene it may be resolved in hours or days. >> a picture is starting to emerge of james holmes. the 24-year-old from san diego had dropped out of medical school. police say he had nothing but a speeding ticket on his record, no connection to the military, but he came prepared to kill. >> columbine high school, the scene of a mass killing 20 years ago is just a few miles down the road and now another community has been struck by a senseless act of violence. in an election year, it will reopen the debate into gun control, of which there are few in colorado. >> we may never understand what lead anybody to terrorize their fellow human beings like this. such violence, such evil is senseless. >